A tool case has a lid and a base, and a panel arranged therebetween. Various structures are used to trap or otherwise retain tools, tool items or other stored items, such that they cannot accidentally fall out of their “home” positions, but such that they are readily removable by the user when desired. Such structures include, for example, retractable stops, depressions beneath stored items, weight-biased pivoting of holders, spring biasing of holders, trapping of items by the lid or by other item holders within the case, and various clip arrangements. Preferably the lid is transparent, and the tools or other items are arranged by height in step-wise fashion, the panel being stepped accordingly, to maximize visibility.